Image display on a liquid crystal display (LCD) panel is controlled by adjusting orientations of liquid crystal molecules within the LCD panel. Each liquid crystal molecule has a birefringent property, which can result in undesired color shift and a relatively narrow viewing angle. To reduce the color shift, a multi-domain vertical alignment (MVA) mode LCD panel may be used. In a 4-domain vertical alignment mode LCD panel, each pixel area (hereinafter, “pixel”) of the LCD panel is divided into four regions by formation of a pattern on electrodes of the pixel. The pattern may be of protrusions, or of openings, or a combination of these. The pattern is configured such that the liquid crystal molecules in each region of the pixel can be inclined at a particular angular orientation, with the angular orientations in all four regions being different from each other. Thereby, reduced color shift and a broadened viewing angle can be achieved. However, despite such improvements, the display provided by a 4-domain vertical alignment mode LCD panel may still be considered as unsatisfactory. As such, an 8-domain vertical alignment mode LCD panel may provide superior display. In the 8-domain vertical alignment mode LCD panel, each pixel is divided into two sub-pixel units having different operating voltages. Each of the sub-pixel units is divided into four regions through the aforementioned 4-domain vertical alignment mode LCD panel techniques. The combined effect is to provide eight regions for one pixel, with angular orientations of liquid crystal molecules in all eight regions being different from each other.
Referring to FIG. 4, a conventional 8-domain vertical alignment mode LCD panel includes a plurality of scan lines (SL) and a plurality of data lines (DL), which cross each other and cooperatively define a plurality of pixels 9. In addition to four regions (4-domain) using the aforementioned techniques, each pixel 9 is further divided into first and second pixel sub-regions 91, 92. The first pixel sub-region 91 is provided with a thin film transistor 910 coupled to one of the scan lines (SL) and one of the data lines (DL), and a first capacitor assembly coupled to the thin film transistor 910. The capacitor assembly has a first liquid crystal capacitor 912, and a first storage capacitor 913 coupled to the first liquid crystal capacitor 912 in parallel. The second pixel sub-region 92 is provided with a second liquid crystal capacitor 922, a second storage capacitor 923 coupled to the second liquid crystal capacitor 922 in parallel, and a coupling capacitor 921 coupled to the second liquid crystal capacitor 922. The assembly of the second liquid crystal capacitor 922, the second storage capacitor 923 and the coupling capacitor 921 is coupled to the assembly of the first liquid crystal capacitor 912 and the first storage capacitor 913 in parallel. When the thin film transistor 910 is activated by the scan line (SL), a voltage signal is transmitted through the data line (DL) to charge the first liquid crystal capacitor 912 and the first storage capacitor 913, and to charge the second liquid crystal capacitor 922 and the second storage capacitor 923 through the coupling capacitor 921. Due to the use of the coupling capacitor 921, the first and second liquid crystal capacitors 912, 922 exhibit different voltages during charging. As a consequence, the twisted angles of the liquid crystal molecules of the first liquid crystal capacitor 912 in the first pixel sub-region 91 differ from those of the liquid crystal molecules of the second liquid crystal capacitor 922 in the second pixel sub-region 92. Thereby, an 8-domain vertical alignment mode display is realized.
The conventional 8-domain vertical alignment mode LCD panel is disadvantageous in that residual charges in the second liquid crystal capacitor 922 resulting from previous charging cannot be sufficiently discharged prior to subsequent charging of the first and second liquid crystal capacitors 912, 922, thereby resulting in image sticking and reduced display quality.
Therefore, a means and a method are desirable to overcome the limitations described.